Air carrier Captain reported inadvertently crossing a hold short line due to overgrown grass obstructing signage and a lack of labeling on the WBSB airport diagram.

Narrative

At WBSB; we were given taxi instructions from the military side of the airport to exit M1; turn right and hold short of Runway 03 at W4. The airport diagram on the EFB has no identifiers for the military taxiways. The only description of W4 is in the temporary construction page which shows W4 at the end of 03. The grass was also overgrown around the taxiway which obscured the signs identifying our current position. While taxiing; we were given our clearance from ATC. As we confirmed the instructions; verified our position on the EFB; we missed the hold short line that was not at the end of the runway; but several hundred feet down the taxiway. I was taxiing to the sign at the end of the runway and not looking close in to see the hold short line. Once past the line ATC asked if we were going to stop at W4. Thinking the hold short line was ahead of us; we replied we were approaching W4. ATC informed us we had passed the line and gave us instructions to line up and wait on Runway 03. We took off without further incident and completed the flight without complication.We were still on the extended parallel taxiway and did not enter the actual runway environment. No metal was bent; and no aircraft was in danger. Cause: This set of flights was much delayed (17 hrs from originally scheduled) due the maintenance issues; fatigue calls; and time restrictive NOTAMS. While I did not judge myself to be fatigued; I was also not at 100% 12 hours into my duty day. At an unfamiliar airport; with task saturation; I should have stopped the plane when we were given our clearance and confirmed our position without assuming the hold short line placement.